Thomas t bathurst



T.'T. BATHURST.

SPARK PLUG.

APPLICATION FILED AUG-27,` 192I..

Reissued au 31 atto: nu?

UNITED STATES THOMAS T. BATI-IURST, OF KANSAS CITY, MISSOURI, ASSIGNOR TO BATHURST-MANU-- PATENT OFFICE.

EACTURING COMPANY, OF KANSAS CITY, MISSOURI, A CORPORATION.

SPARK PLUG.

Specification of Reissued Letters Patent. Reissued Jan. 31, 1922.

Original No. 1,384,818, dated July 13, 1921, Serial No. 344,717, lfiled December 13, 1919. Application for reissue filed August 27, 1921.

il 'o aU whom t .may oonern:

Be it known that I, T HoMAs T. BATHURST, a citizen of the United States, and resident `of Kansas City, in the county of Jackson andV Sta-te of issouri, have invented certain new and useful Improvements in Spark Plugs, of whichf the following is a specification.

This invention relates to spark plugs in general, but, in some of its features, has special applicability to the class of. so-called self-cleaning spark plugs which are provided with means whereby cleaning fluid l(which may be the fuel itself) may be passed over and around the electrodes without removing the plug from the engine.

`The invention'has for an object anim-v proved construction of spark plug which will lend itself more readily than known constructions to inspection of the sparking points and porcelaine; to cleaning of the same, whether by the self-cleaning method mentioned above, or by direct manual application to the faulty art; and to priming through the spark p ug, making priming cups unnecessary.

Further objects and advantages attained by my invention, and novel details of construction, will be noted in the course of the following description of a preferred embodiment of my invention. It will be readily understood that in many details change of form and proportion may be made without departing from the spirit of the invention.

In the drawings:

Fig. 1 is an external view of a spark plug,

constructed in accordance with my invention; x

Fig. 2 is a central sectional view, the porcelain being shown in elevation; and

Fig. 3 is a fragmentary view of one part of the spark plug, showing the sparking points modified in a manner to be hereinafter described.

Referring now to the drawings in detail, 1 represents the porcelain, which may be of any usual or suitable construction ;v as shown, an electrode 2 extends longitudinally through the porcelain andis threaded at its upper end to receive binding nutl 3, and at its lower end projects a short distance below member 10.

celain 1 is provided with the usual enlargement orbase 4, upon which are clamped the Intermediate its ends, por-v Seral No. 496.142.

portant consequence of the construction here' inafter referred to, that the tight clamping engagement of the nuts 5, 6, with the base 4 of the porcelain needr never be disturbed unless it becomesfnecessary to renew the porcelain. It is well known that the seating of `the porcelain in the metal parts which support it should be permanent, if possible, in view of the fact that it is a difficult matter to reseat the porcelain without subjecting 1t to strain.

Referring now to the shell of my improved spark plug, it will be noted that it is made up of a lower member 10 and an upper member 11.' The upper member 11 is of the character of a draw nut, having an annular flange 12 loosely fitting in the space between nuts 5, 6, and an internal thread on its lower portion. The lower member 10 comprises a central polygonal nut portion and upper and lower externally threaded extensions 13, 14. The threaded extension 13 engages the threaded portion of upper member 11, and the extension 14 is adapted to be screwed into the usual socket openings of an internal combustion engine (not shown).

p Coacting with central electrode 2 are a pair of electrodes 15, 15, formed of pieces of wire bent into semi-circular shape and having their ends embedded '1n the member 10.

'The normal sparking point for the electrodes 15, 15 is at their intersection 19, but in the event that the electrodes 15, 15 become burned out at the intersection 19, the shortened pieces 'of wire maybe bent inwardly and upwardly toward electrode 2 in order to readjust the spark gap.

The upper lip 16 of member 10 is shaped to conform to the flange 7, the former thus constituting a seat for the latter when the parts are drawn together in the manner hereinafter referred to. A packing ring of any suitable material may be interposed between flange 7 and seat 16.

. The side wall of member 11 is pierced by a series of holese 17, which thus establish communication b tween the atmosphere and annular recess 18, formed by reducing the outsideA diameter of draw nut adjacent said l holes. The holes 17 should be positionedl sufliciently high up onl member 11 so that vthey will not be masked by themember 10 `when the two members are drawn together.

I will now describe the manner in which` my improved spark plug operates' and may be manipulated in realizing the objects of invention recited above. v The spark plug, asl-above descrlbed, is separable into two parts by rotating the member l11 on the member 10., That is to say, the porcelain, together with the central electrode; binding nut, clamping nuts 5, 6, and member l1, can be withdrawn from member 10. It is desirable to effect this separationV prior to inserting the plug in the engine, as one is thus enabled to apply a heavy wrench lto the part 10 and screw 1t firmly into .the

engine socket without danger to the orcelain in case the wrench should slip.

with its connected parts may be inserted and firmly 'united with member 1() by screwin member 11 down tightly. As thus assemble a unitary" spark plug 1s constituted, having. v a strong protective shell comprising the ,ele-

ments 10, 11, 5, 6, this shell being made perfectly airftight by reason of the close seating of flange 7 on the seat 16.

For priming or forcleaning the sparking points, the member 11 is unscrewed a few turns, whereupon the flange 12,' acting against the head of nut 5,-will lift the porcelain 1 and raise the flange 7 oil? the seat 16. The parts are shown in this lrelation in Fig. 11, and it will be seen that fuel or cleaning 'I fluid may be introduced into the cylinder ofthe engine, passing over the sparklng l electrodes or porcelain.

points, by way of the holes 17, recess 18,

`valve-7, 16, and bore of member 10. Similarly, the engine can be permitted to exhaust through the same passage if it is desired to blow out, in this way, accumulations 'of carbon or other extraneous matter on the If it is desired tov inspect the sparking v points or to test `the porcelain or clean it manually, the member 11 may be entirely unscrewed and "lifted off the lug 10, leaving the latter in the engine. Iii doing this it willnot benecessary to disconnect the wires from the binding post, inasmuch as the plllember 11 can be Vrotated independently of orcelain.

h en the porcelain with its "connected yparts has been withdrawn, the lower half of the rcelalin, belowits base 4, ivill be expose thus ypermitting the surface of this part, which is exposed to the explosions of the engine, to be manually cleaned.` Also,

hen Aplug member l() is in place, the porcelain the porcelain can be effectively tested for fractures below the base 4, an operation v which cannot be satisfactorily accomplished in spark plugs of known types without unseating the porcelain, the lower end of which is usuall inaccessible by reason of its being surroun ed by the lower part of the-shell. y

, Claims:

1. In a spark. plug, the combination with a central insulating electrode holder, cfa hollow socket member, a draw nut rotatably connected with said electrode holder andmember, coacting valve seats on said electrode holder and sa1d socket member, respectively, a recess between sa1d draw nut and `having threaded engagement with said socket said electrode holder, said recess being contiguous to said valve seats, and ports establishing communication between said recess and atmosphere. l

2. A spark plug according to claim 1, in which the ports are located in the. side of the draw nut.

3. In a spark plug, the combination of a shell, a central electrode supported in said shell and having its lower end projecting below said' shell, and a. second electrode, comprising an arched wire having its ends secured to said shell-and, its midportion at the sparkingv distance ,from said central electrode.

4. A spark plug comprising a central insulating electrode holder, a hollo'w socket member, a member Arotatably secured to said electrode holder, said electrode holder being formed so as to provide an air space between it and the rotatable member, said rotatable member adapted to4 separately unite said holder and hollow socket member.

5. A spark plug comprising a core of insulating material carrying one electrode, a holder for sa1d core adapted to engage the core intermediate its ends, a hollow socket member, sa1d core havlng lts lower end reduced to provlde an annular space between `it and the socket member, a rotatable `member for unitin said holder with said socket member, said older being shaped so as to provide `an air space between it and said rotatable member. i

6. A spark plug comprising a central insulating electrode holder, a hollow'socket member, an independentl rotatable member mounted on said electro e holder for uniting said. holder with said' socket member, said electrode holder beingreduced to form anannular recess andf"said rotatable member having ports" establishing communication between saidrecess and the atmosphere.

THOMAS T. BATHURSTQ 

